In the related art, a method of measuring the resistance of a transparent conductive film formed on a light-transmissive substrate by utilizing optical transmission/reflection characteristics of the material is known (for example, see Patent Literature 1).
Patent Literature 1 discloses a technology in which, for example, a solar-cell substrate provided with a transparent conductive film is irradiated with light in a solar-cell manufacturing line, so as to evaluate the characteristics of the transparent conductive film on the basis of the reflectivity calculated from the light intensity of the irradiated light and the light intensity of reflected light.